#include <stdio.h>

int main()
{	   		   
    int i, j, n;
    long term, sum = 0; //1
    printf("Input n:\n");
    scanf("%d", &n);
    for (i = 1; i <= 2 * n - 1; i = i + 2) //3
    {	   		   
        term = 1; //1
        for (j = 1; j <= i; j++) //3
        {	   		   
            term = term * j; //1
        }
        sum = sum + term;
    }
    printf("%ld", sum);
    return 0;
}	   		